It is known in the art to reduce or prevent spoilage of oxidizable flowable materials by maintaining in a container for the flowable materials an inert atmosphere and it is also known to provide means whereby pressurized containers have means for releasing the internal pressure before the container lid is removed. Examples of the prior art showing such methods and means comprise the Lane U.S. Pat. No. 3,883,043 and the Kollsman U.S. Pat. No. 2,593,770.